GNU/Linux Distros in which systemd can be replaced

Exherbo has been removed from MainPage Exherbo Linux
"systemd is the default init system, but you can disable systemd usage globally and use alternatives easily." See Without systemd.
The fact that systemd can be disabled/replaced is also true for most other GNU/Linux distros with systemd as default init (expect the ones from Red Hat, eg Fedora, RHEL, CentOS).

Additionally, software repositories such as those from Devuan can be added to improve System V init compatibility.

ALT Linux is derived from Mandrake. Prior releases did use PID1 systemd, but does the "Jan2017 Sisyphus" release have systemd as default init?

Reply -- CrayXMP -- ALT Linux
Their wiki has some English. Sisyphus can be seen as a testing/unstable repo :
"Sisyphus is quite dynamic project which makes it hard to schedule and perform releases based on it."
They release nightly images and branches every few months however.
We can notice that the following sources suggest that systemd is actively used : ChangeLog; BUGS or the russian wiki page on systemd.
To be fair, experimental downloads using GNUstep, IceWM and WindowMaker flavours use sysvinit. But these are obviously not mainstream Desktop Environments.
I tried the latest branch alt-workstation-8-x86_64.iso (which happens to be a MATE desktop) and then installed sysvinit related packages to remove the systemd process as PID1. Except from the systemd package itself I was not able to remove the systemd related packages because of their deep dependencies. I even shifted the repos to sisyphus under apt (p8/branch --> Sisyphus) to confirm it.
To sum it up: ALT defaults to systemd as PID1 and as such is actively developed.
Even if it was easy to install sysvinit and remove the systemd process only, fully removing the systemd packages leads to unwanted consequences on the desktop. This could explain that sysvinit has been limited to some very light DE (with no forced dependencies to systemd).
It is their choice to use the systemd way, and it is our choice not to entrap ourselves in it.
According to this little experiment I thus recommend to definitely exclude ALT Linux from the list of systemd-safe distros.

Nonfree OS?

Should we list nonfree operating systems like HP-UX?
I think our listings here should cover only free software (or open source, if you prefer that term).
That spans nearly all GNU/Linux and *BSD systems plus some exotic systems like ReactOS or illumos. What do you think?

I agree. I only added a bunch of non-free OSs (mostly Unix) as someone else had started it but you're right, it's better that we don't include them. -- wicket

Feb2017 -- kriv removed Leenux mainpage listing. It is a commercial product; I can't locate a link to d/l source, and cannot verify its init.

Non general purpose OSs?

Should we be listing non general purpose OSs like FreeNAS? We could go on forever listing them all and it detracts from the point we are trying to make. -- wicket

I appreciate seeing the few already listed to the breakout section titled "Embedded", would not wish to see those entries removed. Although I'm not personally motivated to add additional non-general-purpose entries, fine by me if someone from such a project shows up here to add a listing for their project. -- kriv

Other systems without systemd

I added Dyson, as I found no systemd in their repos. However, how do we gauge the likeliyhood that any of the OSes listed here remains clean? Do any of them have an explicit commitment? In that case, it would be great to point directly to it, rather than the generic page. Ale2015 09:38, 1 January 2015 (UTC)

The likelihood of non-Linux OSs like Dyson remaining systemd-free is very high as systemd is not portable. One of those currently listed that concerns me is gNewSense, which being based on Debian, will probably adopt systemd with its next release. -- wicket

Gentoo

From the edit history:

true Gentoo default is OpenRC and offering a user-unfriendly way to protect one's self from sysd Portage input, but it will disappear.

Please cite your source on this. I've been a Gentoo user for years now, and if Gentoo was intending to switch to systemd only, or even putting it in the stage3, I think I would have heard about it by now. (As an aside, USE="-systemd" comes quite naturally to Gentoo users, and the distro was never designed around "user friendliness" anyway, so I'm not sure the point about it being user-unfriendly is valid, especially when it comes to init systems, a component which most users don't care about)

Concerning Void Linux (and others?)

I followed the link on the main page to Void Linux, downloaded and ran the LiveUsb + Cinnamon. I now wonder why it is listed here.

It is listed here since Void's default init system is runit. Check it via "ps -fp 1".
Although it may contain some shimmed systemd components, but it does not run systemd as PID 1.

Should we list older Trisquel 6.0 and maybe 7.0 ?

Trisquel is one of the libre distributions recommended by the FSF. Trisquel 6.0 (still supported) doesn't have any trace of systemd on it. It's successor Trisquel 7.0 has a systemd-services and systemd-shim package installed along with a virtual systemd package. It is based on ubuntu though so the next LTS release might have to use systemd. Should either Trisquel 6 or 7 be added to the list of distributions without systemd ?

PS: The kernels in both versions of Trisquel live CDs are dated but you can upgrade them up 3.5.x ( with backports for Trisquel 6.0 ) and 4.2.x for Trisquel 7.0 at the time of this writing.)

reply: -- kriv IMO, no (neither Trisquel 6 nor 7) should be listed. Although a fan of Trisquel, I count that project among those "now infected". Mentioning Trisquel here, off mainpage, is fine. Linking/mentioning "but but older version XYZ is systemd-free" seems pointless (track/list old version how far back?)
ref: trisquel T6=2013, T7=2014 w/systemd

Consider Respin Rearrangement

Would it make more sense to have respins as indented entries under their origin distro? Such as having the Devuan respins listed snug under Devuan, Calculate under Gentoo, etc etc.

Reader ought to have a heads-up whether a given project really stands as a "distro" (has a domain homepage, has a dedicated forumsite) vs is just a onemanband project supporting six niche users. THAT will become increasingly salient as the number of (easy-to-create) respins blossoms. Example: "Yay! Anudder player! Run over to without-systemd.org and add MiyoLinux to the list." (sez me)(IOW, i did so) A week later, um, well... MiyoLinux dev already announcing "sorry, I won't be continuing development". So, looking forward, I'm not enthusiastic about jerking readers' chains by linking to nascent projects, but if someone cares to list a given project at least the tabular info (or lack thereof) would provide reader a clue whether a project is a "serious" (has domainsite, has forum site) endeavor.

So, I hear ya about creating a breakout/hierarchy according to parent, but still believe a tablular presentaion would be preferable. Bonus points for "clickable, click to sort" column headers. That functionality would enable a reader to easily find a project's siblings, or quickly find most recently released, or whatever.

Upon pasting the result and clicking "Show Preview", I noted that the 1270+ lines of "code" spewed by the generator DOES render a working table
(had to manually add 'sortable' to the table declaration)
but "all that code" would be far, far too unwieldy to manually manage/revise/update. Sigh.